Machine for processing sheets



Oct. 15, 1968 G. SCHOCH 3,405,937

MACHINE FOR PROCESSING SHEETS Filed June 14, 1967 5 Sheets-Sheet l Oct. 15, 1968 s. SCHOCH MACHINE FOR PROCESSING SHEETS 5 Sheets-Sheet 2 Filed June 14, 1967 PRIOR ART PRIOR ART PRIOR ART PRIOR ART G. SCHOCH Oct. 15, 1968 MACHINE FOR PROCESSING SHEETS 3 Sheets-Sheet 5 Filed June 14, 1967 United States MACHINE FOR PROCESSING SHEETS Gregor Schoch, Chemin de la Roche 16,

Renens, Switzerland Filed June 14, 1967, Ser. No. 646,088 Claims priority, application Switzerland, June 21, 1966, 9,075/ 66 9 Claims. (Cl. 27179) ABSTRACT or THE DISCLOSURE A machine in which gripping bars are advanced by a chain to engage sheets in a first position and advance the sheets to an operating position in a press, the chains and bars being periodically immobilized in the engaging and operating positions, there being provided a mechanism constituted by a cam operating a stem which in turn operates a balance member coupled to a lever mounted on a drive shaft for the chain wheels, to lock the drive shaft when the bars are in the aforesaid positions and thereafter to pivotally move the balance member, lever and drive shaft as a unit about the axis of the drive shaft such that the latter turns through a small angle and advances the gripper bars a small distance in their direction of advance after they have been immobilized.

Brief summary of the invention The invention is directed to a machine for processing sheets, and in particular to a press which rule bleeds or stamps cardboard sheets which are transported one by one by gripping bars advanced by two endless chains which are alternatively driven and immobilized.

In such machines, it is difiicult to attain both high speed and perfect precision, because of the inertia of the masses concerned which, on the one hand oppose the rapid succession of stopping and advance and, on the other hand subject the chains to irregular wear and tear which makes it virtually impossible to ensure the accurate position of the sheets.

However, it is absolutely necessary to make sure that the immobilization of the bars occurs in an exact controlled position, both at the station at which the sheets are removed from the press as Well as at the station at which they are processed.

It is an object of the invention to overcome the above disadvantages by providing apparatus ensuring precise positioning of the sheets while enabling high speed operation of the press.

In accordance with the invention, there is provided a mechanism for acting on the drive shaft of the wheels which drive the chains, to lock the wheels When the stop during stoppage of the bars, after which the drive shaft is advanced slightly to advance the bars, the mechanism being characterized by the provision of a single cam with four distinct surfaces which acts on a stem which controls pivotal movement of a balance member pivoted to a lever which is supported on the driving shaft and which serves to lock and advance the drive shaft, the lever being independently acted on by an elastic means which urges the lever to an adjustable rest position.

Brief description of the drawing FIGURE 1 is a diagrammatic side view of the general arrangement of a press;

FIGURES 2 and 3 are sectional views through the press showing in different positions a known arrangement for driving the chain wheels;

FIGURE 4 is a side view of the arrangement shown in FIGS. 2 and 3;

FIGURE 5 shows a known modification for the ar- 3,405,937. Patented Oct. 15, 1968 rangement of FIGS. 24 for supplemental displacement of the chains;

FIGURE 6 is a diagrammatic Side view of a mechanism according to the invention for obtaining supplemental displacement of the chains, the illustrated position showing locking of the drive shaft.

FIGURES 7 and 8 show a detail of the mechanism of FIG. 6 in different positions, FIG. 7 showing released position of the drive, FIG. 7 showing released position of the drive shaft, and FIG. 8 showing the position after supplemental displacement of the drive shaft; and

FIGURE 9 is a view on enlarged scale showing the surface of the cam controlling the operation of the mechanism.

Detailed description In FIG. 1 there is shown a press, in side view, with framework 1, a lower platen 2 which moves up and down, chains 3 engaging gripping bars, and front chain wheels 4 and back chain wheels 5.

Each time a bar reaches position A under the wheel 4, it seizes a sheet, and after a turn of said wheel, the bar reaches position B Where it maintains the sheet between the framework 1 and platen 2 in order for the sheet to be processed. In these two positions, the sheets must be exactly positioned Heretofore it has been known to advance the bars slightly in each cycle and then to move the bars against straightening stops, the chain portions between the two stations being slightly slackened, due to a more marked backward motion of the bar at station B.

The mechanism shown in FIGS. 2 to 4 has already been developed in order to impart to the front chain wheels 4 rapid rotations of exactly one turn. A knowedge of this mechanism is essential since it plays an important part in the present invention.

FIG. 2 shows a wheel 4 rigidly secured on an axle 6 which passes through a wall 7 of the press and fixedly supports a grooved cylinder 8 on which a sleeve 9 is axially slidable.

In the position of the sleeve in FIG. 2, grippers 10 on the sleeve mesh with grippers 11 of a pinion 12, to which a cogged segment 13 transmits a rotary motion alternately in one direction and in the opposite direction (see FIG. 4). The arrangement is such that the sleeve 9 meshes with pinion 12 when the latter turns in the direction corresponding to that of the displacement of the chains. The sizes of .the pinion 12, segment 13, and a driving connecting rod 14 and crankshaft 15 are such that the wheels 4 perform one turn for each stroke of segment 13.

In FIG. 3, the sleeve 9 has been shifted axially and no longer is in mesh with pinion 12 but rather is engaged with fixed grippers 16 on the wall 7. This ensures the immobility of the axle 6 and of the wheels 4 after each turn of the latter, that is at the time when the gripping bars occupy the positions A and B in FIG. 1.

The displacement of the sleeve 9 is efliected by a lateral cam 17 integral with crankshaft 15 and governing the rotation of a fork 18.

Making use of the main elements of the already de scribed arrangement, it has already been proposed, upon each stoppage of the chains, to correct the position of the bar in the engaging station of a sheet (Station A) and that of the bar :in the working station of a sheet (Station B) by imparting to the chains an additional feed in the conveying direction, to apply said bars against stops at exactly predetermined position. This position readjustment in the conveying direction of the bars is particularly advantageous, as compared to reaward readjustment, in the case of thin sheets which cannot correctly move back, both by reason of their lack of rigidity, as well as because of the rapid motion of the machine.

With reference to FIG. 1, it is easily seen that if stops 19 and 20 are raised slightly ahead of the bars in positions A and B, it will be suiiicient to transmit to the chains 3 an additional feed to bring the bars into contact with these stops in order to fix very accurately the position thereof. This is made possible by transmitting to the wheels 4 a supplemental rotatory motion after each turn thereof.

In reality, the dimensions shown in FIG. 1 are exaggerated, the additional feed of the bars being of a very small amount.

As has been seen by the description of FIGS. 2 to 4, the arrangement therein opposes any additional feed of the chains, since upon each stop of the chains, fixed grippers 16 of the machine framework bring the sleeve 9 to a standstill.

It has already been proposed to replace these fixed grippers by the arrangement according to FIG. 5, where gripper-s 16 are arranged on a disk 21 coaxial with shaft 6, a connecting rod 22 being adapted to turn the disk 21 around the shaft 6.

The rotational direction of disk 21 is the same as that for the feed of the chains, i.e., in the direction of arrow 23, whereby displacement of connecting rod 22 downwardly will make it possible, each time the sleeve 9 is engaged with grippers 16', during immobilization of the chain, to transmit to the wheels an additional feed.

This additional feed takes place as soon as the grippers 10 of the sleeve 9 are completely released from the grippers 11 of inion 12, which then performs an idle return. Of course, said feed will be carried out before the tools touch the sheet. As soon as the sheet is released from the pressure of the tools, a return motion in a direction opposit the arrow takes place, in order that the grippers 10 of sleeve 9 are again facing the grippers 11 of the driving pinion. The backward motion of the sheet which results therefrom is unimportant, since the sheet has already been processed.

The necessary displacements of the connecting rod 22 are transmitted to it by cam 17 on the shaft 24 (see FIG. 4).

Reverting now to FIG. 1, it is clear that if the stoppage of the bar in positionA against the stop or stops 19 can be brought about directly by the wheels 4, the stoppage in position B against'the stop or stops 20 is brought about by the traction of the chain portions uniting point B to the wheels 4 over the wheels 5.

In order to obtain accurate stoppage or rest, it is necessary to exert sufficient pull on the chains. This is effected by making them carry out, by means of the described movable grippers 1 6' a displacement slightly greater than the path to be covered for reaching the rest position against stop 20, the excess being on the one hand, partly absorbed by the chains and partly by a shifting of the wheels against the pull of springs 25, urging the axle of the wheels backwards.

An advantage of this additional feed of the bar keeping the sheet in working position in relation to the devices in which on the contrary use is made of a backward motion of the still unprocessed sheet, lies in particular in the fact that the feed stretches the sheet, whereas a backward motion is liable to make it how between the platens, particularly with thin material.

Another means for obtaining the aforesaid additional feed has already been proposed, which consists in making the driving member of the chains integral with a cam, in a notch of which a roller is periodically pressed, thus fixing the standstill position of this member and receiving, upon each working cycle, a motion suitable to transmit to the driving member of the chains an angular shifting of predetermined amount in the conveying direction of the chains.

The present invention refers to a machine making use of such an arrangement. It provides a lever concentric with the driving member of the chains and elastically maintained at rest against a stop opposing its rotation in a direction opposite that of the said driving member, said lever bearing a knuckle pivot of a balance whose arms extend on either side of the articulation and partly surround the driving member, the arm opposite the stop bearing a locking member and the opposite arm being pulled by a traction stem controlled such that during each working cycle it keeps the balance in position away from the locking notch of the cam, after which it then brings about the application of the locking member into the notch of the cam, exerting thereupon an additional pull causing the balance locked with the cam and the lever supporting it, to oscillate together coaxially with respect to the driving member to transmit thereto an additional feeding motion, whereupon the lever momentarily leaves its rest against the stop, whereafter, the traction of the bar ceases and the aforesaid members return to their starting positions and the described operative cycle starts again.

In FIGS. 6-9, there is shown at 26 the drive shaft of the driving member of the chains, namely the wheels 27 driving the conveying chains 28. The wheels 27 are rigid with a cam 29. The shaft 26 corresponds to the shaft 6 of the machine of FIGS. 2 to 5, driven by the segment 13 already described hereinabove.

The cam 29 constitutes one of the two members ensuring the immobilization of the chain wheels 27, when a conveying gripping bar occupies a station where it seizes a fed sheet, while another bar holds another sheet in working position.

The other member of immobilization is a locking roller 30 which a balance or two armed lever 31 periodically drives into a notch 32 of cam 29.

This function is governed by the cam 33, acting on the balance 31 through lever 34, pivoted at 35 and a traction stem 36, articulated at the balance end opposite the roller 30. The stem 36 undergoes the action of drawback spring 37 ensuring the engagement of the roller 38 of lever 34 against the cam 33.

In its turn, the balance 31 is pivoted at 39 on a lever 40 adapted to oscillate concentrically on the shaft 26, but normally resting against a stop assembly constituted by a fixed part 41 and a regulating screw 41', under the infiuence of a backward spring 43. The locking roller 30 is at the end of the balance ar-m opposite the stop 41 of lever 40.

In the rest position of lever 40, it is possible that the pivot 39 constitutes a fixed point around which the balance 31 can oscillate between two defined positions.

One of these positions corresponds to that shown in FIG. 7 on an enlarged scale.

In this position, the balance 31 keeps the roller 30 outside the trajectory of the cam 29 and permits the free rotation thereof. When the balance occupies this position, the transport of the gripping bars from one station to the other takes place through rotation of one turn of the chain wheels 27. This position is reached when the roller 38 of lever 34 is at rest on the portion 44 of smallest radius on the cam 33.

The second position, corresponding to FIG. 6 is that of immobilization and locking of the cam 29 and, thereby, of the shaft 26, by engagement of the roller 30 in the notch 32 of the cam 29. This position is reached by exerting a pull on the stem 36, against the action of spring 37, which causes the balance 31 to pivot around its pivot 39, always considered as fixed point. This motion arises due to the fact that the roller 38 of lever 34 is pushed back by the ramp 45 of the cam 33 turning in the direction of the arrow 46 (see also the partial detail of the section of the cam in FIG. 9). The position represented does not correspond, however, to the maximum radius of the cam, rather the position is that at intermediary point 48 at which the cam 29 is locked by means of the pressure roller 30. The section of the cam 33 shown to a larger scale in FIG. 9 allows seeing in detail what happens during the locking and thereafter.

The cam undergoes a uniform rotatory motion of one turn per working cycle, corresponding to successive intermittent rotations of one turn per working cycle of the shaft 26. The cam 33 continues turning during stoppage of shaft 26. At the moment of stoppage of shaft 26, the roller 38 of lever 34 reaches a new ramp, very smooth, designated by numeral 49, and located between the top 48 of the ramp 45 and the maximum radius 47 of the cam. This new ramp 49 gives rise to a new pull, of very weak amplitude, on the stem 36 and thereby on the balance 31.

At this moment, the mechanism is in the position of FIG. 6, wherein the roller 30 is engaged in the notch 32 in the cam 29 and the balance 31 can no longer turn around its pivot 39.

There then occurs a movement as represented with exaggerated amplitude as shown in FIG. 8.

Therein, the balance 31 tends to turn around the pressure roller 30 as an instantaneous rotation center in the direction of the arrow 50, which rotation would be possible if the pivot 39 did not connect the balance 31 to the axle 26 (represented here by a point) through lever 40. This connection now causes the three centers 26, 30 and 39 to form a set resistant triangle and it is consequently necessary to consider the balance 31 as rigidly connected to lever 40.

Under the effect of the aforementioned additional pull of the stem 36, this assembly of balance 31, roller 30, cam 29, shaft 26, and lever 40, will turn around the axis of shaft 26, the lever 40 being lifted from its stop 41 against the action of the spring 43, as shown in FIG. 8.

The shaft 26 will therefore perform a slight rotation in the direction of the arrow 51 which is its normal rotational direction during each working cycle, and the described mechanism will thus have effected an additional feed of the shaft of the chain wheels, between the locking position of FIG. 6 and the position just described of FIG. 8.

Cam 33 is given a symmetrical form in relation to the diameter x-y (see FIG. 6), so that after locking (FIG. 6) and additional feed of the cam 29 (FIG. 8), a return to the locking position (FIG. 6) takes place, followed by the release of the cam (FIG. 7).

In contrast with the arrangements previously adopted, also making use of a cam and a locking roller, the present invention offers the advantage of the use of a sole control cam 33 operating positively on a single traction stem 36, whereas previously two cams and two stems were necessary, one controlling a part serving as lever 40 and the other of the balance 31.

It is obvious, on the other hand, that the arrangement according to the present invention can work only under certain shaping conditions of its constituent parts. These conditions are, that the balance must surround the shaft 26 driven in such a way that the centers of that shaft, the locking roller 30 and the articulation 52 of the stem 36 at the opposite end of the balance are approximately on a common diameter, which requires that balance 31 extends substantially over an arc of 180, the pull of the stem 36 being so as to be inclined with such diameter. A perpendicular position of the stem would be the most efficient, requiring the least force.

What is claimed is:

1. In a machine for processing sheets of the type having gripping bars for the sheets, chains driven by a pair of motive wheels for advancing the gripping bars, the wheels being driven with predetermined angular displacements, alternating with periods of immobilization, established by periodic engagement of a locking member in a notch of a cam integral with a drive shaft of the chain wheels, through which an angular motion of additional feed is transmitted to the chains at the beginning of each period of immobilization, an improvement comprising a lever rotatably and concentrically mounted on the drive shaft of the chain wheels, means elastically acting on the lever to urge the lever to a rest position and to oppose rotation of the lever in a direction corresponding to advance of the chains, a balance member, a pivot connecting the balance member on the lever, said balance member including arms extending on either side of said pivot and in part encircling the drive shaft, a locking member on one of said arms for engaging the notch in the cam to lock said drive shaft, a traction stem coupled to the other of said arms, and means acting on said stem to periodically displace the same during each cycle of operation of the gripping bars such that the balance is initially displaced from the cam to enable free rotation of the drive shaft after which the balance member is turned about said pivot until the locking member is engaged in the notch of the cam to immobilize the drive shaft whereupon further displacement of the stem causes the assembly of the balance member blocked with the cam and the supporting lever to pivotally move together coaxially with the drive shaft to impart an additional feeding motion to the chain wheels, the lever momentarily moving from its rest position against the action of the elastic means, Whereafter the stem is released and the aforesaid elements return to their starting positions and the cycle begins anew.

2. A machine as claimed in claim 1, wherein said means acting on the stem comprises a second cam including a first portion having an arc of small radius and corresponding to the position of separation of the locking member from the notch of the first said cam, a second portion extending continuously from the first portion and increasing in radius to define a ramp which produces displacement of the stem which controls engagement of the locking member in the notch of said first cam, and a third portion of increasing radius at a lesser rate than that of the second portion defining a second ramp of lesser slope than that of the first ramp for producing displacement of the stem to produce said further displacement thereof which causes the additional feeding motion of the drive shaft, and a fourth portion of maximum radius of the cam extending from the second ramp.

3. A machine as claimed in claim 2, wherein said cam is symmetrical about an axis passing centrally through the first and fourth portions, there being a first and second ramp on either side of said axis joining the first and fourth portions at opposite ends thereof.

4. A machine as claimed in claim 2, wherein said means acting on the stem comprises a pivoted lever coupled to said stem and a roller on said lever in contact with the second cam.

5. A machine as claimed in claim 2, wherein said arms of the balance member extend around the axis of the drive shaft over an arc of about 6. A machine as claimed in claim 5, wherein said stem is coupled to the balance member and extends at an angle with respect to a line joining the ends of the arms.

7. A machine as claimed in claim 1, wherein said arms are respectively coupled to the stem and the locking member about pivotal axes which define an angle with the axis of the drive shaft of about 180.

8. A machine as claimed in claim 1, wherein said means elastically acting on the lever comprises a stop member and a spring acting on the lever to urge the same against the stop member.

9. A machine as claimed in claim 8, wherein said means elastically acting on the lever further comprises means supporting the stop member for adjustment of its position whereby to enable adjustment of the rest position of the lever.

References Cited 

